title: Effect of age at gonadectomy on the probability of dogs becoming overweight.
abstract: OBJECTIVE
  To determine whether gonadectomy or age at gonadectomy was associated with the risk that dogs would subsequently become overweight.
  
  
  METHODS
  Retrospective cohort study.
  
  
  METHODS
  1,930 dogs gonadectomized between 1998 and 2001 at ≤ 6 months of age (n = 782), > 6 months to ≤ 1 year of age (861), or > 1 to ≤ 5 years of age (287) and 1,669 sexually intact dogs.
  
  
  METHODS
  Dogs were followed-up through medical records for ≥ 10 years or until a diagnosis of overweight (defined as overweight, obese, or having a body condition score ≥ 4/5) was recorded. Information extracted included age at study entry, sex, breed, breed-size category, hospital visit frequency, and diagnosis (yes or no) of overweight or diseases that might affect body condition. Relative risk of a diagnosis of overweight was assessed among age groups of gonadectomized dogs and between gonadectomized and sexually intact dogs.
  
  
  RESULTS
  No difference was detected among dogs grouped according to age at gonadectomy with respect to the risk of being overweight. This risk was significantly greater in gonadectomized dogs than in sexually intact dogs, but only during the first 2 years after gonadectomy. Sexually intact male dogs were approximately 40% less likely to have this diagnosis (hazard ratio, 0.61; 95% confidence interval, 0.52 to 0.72) than were sexually intact female dogs; no difference in risk between the sexes was evident for gonadectomized dogs.
  
  
  CONCLUSIONS
  Gonadectomized dogs had a greater risk of being overweight than did sexually intact dogs, but this risk was not influenced by age at gonadectomy. Opportunities exist for veterinarians to provide counseling during the first years after gonadectomy to help dogs maintain a healthy weight.
authors.affiliation: Banfield Pet Hospital, 8000 NE Tillamook St, Portland, OR 97213, USA. sandi.lefebvre@banfield.net
authors.forename: Sandra L
authors.initials: SL
authors.lastname: Lefebvre
authors.forename: Mingyin
authors.initials: M
authors.lastname: Yang
authors.forename: Mansen
authors.initials: M
authors.lastname: Wang
authors.forename: Denise A
authors.initials: DA
authors.lastname: Elliott
authors.forename: Preston R
authors.initials: PR
authors.lastname: Buff
authors.forename: Elizabeth M
authors.initials: EM
authors.lastname: Lund
mesh_terms: D000375:Aging; D000818:Animals; D015331:Cohort Studies; D004283:Dog Diseases / Q000209:etiology*; D004285:Dogs; D005260:Female; D007044:Hysterectomy / Q000009:adverse effects / Q000662:veterinary*; D008297:Male; D009919:Orchiectomy / Q000009:adverse effects / Q000662:veterinary*; D010052:Ovariectomy / Q000009:adverse effects / Q000662:veterinary*; D050177:Overweight / Q000209:etiology / Q000662:veterinary*; D012189:Retrospective Studies